500 Illegal Port Command

[bdimon]

Welcome to Core FTP, release ver 1.3, build 1267 (U) -- © 2003
WinSock 2.0
Mem -- 523,756 KB, Virt -- 2,097,024 KB
Started on Friday February 06, 2004 at 10:25:AM
Resolving Blah, Blah, Blah...
Connect socket #764 to Blah, Blah, Blah, port 21...
220 aseap470 FTP server (SecureTransport 4.1.1) ready.
AUTH TLS
334 SSLv23/TLSv1
TLSv1, cipher TLSv1/SSLv3 (DES-CBC3-SHA) - 168 bit
USER Blah, Blah, Blah
331 Password required for avista.
PASS **********
230 Virtual user Blah, Blah, Blahlogged in.
SYST
215 UNIX Type: L8
Keep alive off...
PWD
257 "/" is current directory.
PBSZ 0
235 PBSZ=0
PROT P
200 PROT command successful
PORT 172,29,5,171,56,8
500 Illegal PORT Command.
Attemping PASV mode transfer...
PBSZ 0
235 PBSZ=0
PROT P
200 PROT command successful
PASV
227 Entering Passive Mode (199,5,49,159,136,169)
LIST
Connect socket #784 to 199.5.49.159, port 34985...
timeout
Error loading directory...


What does this PORT command do?

[bdimon]

I selected the PASV box and tried again. This time I got the following:

230 Virtual user ............ logged in.
SYST
215 UNIX Type: L8
Keep alive off...
PWD
257 "/" is current directory.
PBSZ 0
235 PBSZ=0
PROT P
200 PROT command successful
PASV
227 Entering Passive Mode (199,5,49,159,139,154)
LIST
Connect socket #724 to 199.5.49.159, port 35738...


AFter the timeout, CoreFTP asked me if I wanted to try active mode. Then I got the following:

timeout
Attemping Active mode transfer...
PBSZ 0
timeout
PORT 172,29,5,171,94,201
425 Can't open data connection.
Error loading directory...

I am inside a NAT